1. Field of the Invention
The present invention relates generally to the use of optical sensors to detect the presence of petroleum and non-petroleum based liquids, fluids, or products in a sample, medium, or environment.
2. General Background and State of the Art
Systems and methods for detecting leaks of petroleum or other products, in an environment or medium, are well known in the prior art. Most of these techniques use a quantitative approach to identify a leak or to determine leak rate based on a measurement of volumetric changes of the product. The capability of prior art leak detection methods to accurately measure leakage is affected by certain variables such as temperature change, surrounding medium characteristics, product evaporation, and the characteristics of the product. Furthermore, temperature variation, which is a substantial factor, causes dynamic expansion or contraction of the stored product on both a short-term and long-term basis. Indeed, changes in ambient temperature throughout the day are often large enough so as to “mask” the leakage rate to be measured. For example, a change of 0.01° F. per hour in a 10,000 gallon tank will cause a 0.068 gallon change in the product volume per hour, thus offsetting or amplifying an observed leak rate.
Most of the prior art methods for leak detection attempt to compensate for such temperature variations. Some prior art methods of leak detection attempt to measure condensation in the space. There is still a need for a reliable and economical method and apparatus for detecting the presence of a petroleum or non-petroleum fluid in a medium or environment.